1. Field
This disclosure relates to a semiconductor nanocrystal having high luminous efficiency and a narrow full width at half maximum, methods of manufacture thereof, and articles including the same.
2. Description of the Related Art
A semiconductor nanocrystal, which is also called a quantum dot, is a semiconductor material with a nanometer scale crystalline structure and which includes hundreds to thousands of atoms.
Because a semiconductor nanocrystal is very small, it has a large surface area per unit volume and exhibits a quantum confinement effect. Because of the large surface area and quantum confinement effect, the semiconductor nanocrystal has unique physiochemical characteristics which differ from the intrinsic characteristics of a corresponding bulk semiconductor material.
Particularly, because a semiconductor nanocrystal has a size and composition which are selected to provide a selected band gap energy and because the semiconductor nanocrystal has good luminescent characteristics, such as high color purity, researchers are studying methods to use the semiconductor nanocrystal in a display device, a bioluminescent light-emitting device, or the like.
A commercially available semiconductor nanocrystal including Cd has been reported to have excellent characteristics. However, because Cd has environmental issues, there remains a need for a nanometer scale light-emitting material which does not include Cd, is environmentally friendly, and is safe for a human body.
However, it is difficult to select a material which emits visible light because the wavelength of the emitted light depends on the intrinsic band gap of the material itself. As for a Group III-V semiconductor, there has been much research on a nanocrystal based on InP, because InP provides desirable nanocrystal synthesis conditions and a desirable band gap. InP emits infrared light and has a band gap of about 1.4 eV, which is relatively narrow. When an InP nanocrystal is prepared which has a nanometer scale particle size and a larger band gap, the InP nanocrystal emits a blue light, but its stability may deteriorate due to the very small size of the nanocrystals. However, because InAs, which may be easily synthesized using a wet method, has a very narrow band gap of about 0.9 electron volts (eV), InAs nanocrystals may not be readily synthesized to provide a nanocrystal emitting visible light. In addition, because a Group III-V precursor has relatively less reactivity than a Group II-VI precursor, the Group III-V precursor may grow into a nanocrystal at a slower speed, and thus, the Group III-V precursor may provide a nanocrystalline material having a less uniform size distribution than the Group II-VI precursor.